This invention relates to an improved flow control unit for accurately controlling the flow of fluid through a length of flexible I.V. tubing. More particularly, this invention relates to a disposable clamp and flow control member utilizing a roller member to exert a controlled force on a length of tubing and in a manner such that the roller member can be easily inserted into the clamp body yet is captively held therein so that unintentional removal of the roller can only be effected with extreme difficulty.
Clamping devices or fluid flow control units of the type concerned with in this invention are disclosed in U.S. Pat. Nos. 3,685,787; 3,802,463; 3,893,468 and 3,918,675. In U.S. Pat. Nos. 3,685,787 and 3,802,463 open end portions of a clamp body are provided for both insertion of the tubing and placement of a roller clamp with trunnions which ride up a ramp means and onto a guide track. However, even with the roller exerting a compressive force on the tubing so as to offer resistance to movement of the roller, the roller can be inadvertently forced to travel a reverse path down the ramp either by movement of the roller directly or indirectly by a pulling action on the tubing in the direction of the open end of the clamp. Obviously, this is an undesirable condition. In U.S. Pat. Nos. 3,893,468 and 3,918,675 stop members are provided along the roller track so as to prevent dislodgment of the roller. However, these stop members can pose problems in inserting the roller into the clamp body in that the roller member must be force fitted past these stop members which may require considerable force. Further, there is the problem that if the stop members are not of sufficient size or dimension they can be easily broken or do not serve their function and permit the trunnions of the roller to pass around or over them.
It is an advantage of the present invention to provide an improved clamp and flow control unit for flexible tubing wherein a rotatable member can be easily positioned inside a clamp body and retained therein in a secure manner even with extensive forces being exerted on the tubing or the rotatable member. Other advantages are a clamp member with a snap-in roller feature which is easily molded yet durable, is disposable and can accurately control the flow of fluid through flexible tubing.